-What is the population of the metro-area you are doing the study on? Is there a high usage of public transportation in the area?
-Well there is no way you are going to get a level of service of A. But you don't want to have a level of service at F because nothing works then (parking lot like).
-Usually a B is a good goal to aim for on existing highway infrastructure, although a C can be more realistically acheived if there is a lot of autos using the highway. A level of service at D usually means your heading towards highway failure or F. It really depends on the metro area and the percentage of auto-usage among the population.
-Check with your MPO of the area your researching on or contact your state's DOT.
-Remember though, adding existing lanes to highways doen't guarantee traffic decongestion, but sometimes more vehicles using the roadways.
Interesting question. If you are interested in the straight "engineering" answer, then yes - ITE is the authority.
I don't particularly agree with Rumpy Tunanator as to "acceptable levels of service", although as he sort of points out - it depends on where you are. An acceptable level of service in nowheresville U.S.A. will be much different than a heavily urbanized area. Level of Service "E" is generally accepted where I work. We've also moved away from a straight volume to capacity (V over C) analysis and concentrate more on overall travel time, queue lengths, and delay. It's fun stuff.
You might find some useful info here. Definitely a different approach from traditional engineering solutions.
Transportation Research Board, National Research Council, Highway Capacity Manual. Special Report 209 (1998) 3ed. Pg. 3-8 to 3-11.
S. Mark White authored a Planning Advisory Service Report (PAS) titled something like "Transportation Management Systems", which has lots of good information on LOS measures, v/c ratios and capacity based on road design and the functional classification.
Burchell, Robert W.; Listokin, David; William R. Dolphin, Development Impact Assessment Handbook (1994). Pg. 262 -264.
I should clarify. My intention is to first understand the standard way that LOS's are determined and then make ammendments which I assume will be necessary. Ultimately I am trying to determine a maximum road capacity in a dense urban area and then correlate that to a maximum parking capacity.
thanks for the victoria link, and also the person who just posted - including page numbers!
Oops - it's been a while since I was at the ITE page. If you can get your hands on the ITE's "Transportation Planning Handbook", there is a chapter in there about roadway capacity. PM me if you are unable to find this document and I'll see if we can work something out.